Return-Path: <13brv3@bellsouth.net> Received: from imf23aec.mail.bellsouth.net ([205.152.59.71] verified) by logan.com (CommuniGate Pro SMTP 4.1.4) with ESMTP id 2600570 for flyrotary@lancaironline.net; Tue, 23 Sep 2003 15:34:15 -0400 Received: from rad ([68.212.12.251]) by imf23aec.mail.bellsouth.net (InterMail vM.5.01.05.27 201-253-122-126-127-20021220) with ESMTP id <20030923193414.MGWR20055.imf23aec.mail.bellsouth.net@rad> for ; Tue, 23 Sep 2003 15:34:14 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "Flyrotary List" Subject: turbo math Date: Tue, 23 Sep 2003 14:34:14 -0500 Message-ID: <000001c38209$ad9b52a0$0201a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C381DF.C4C54AA0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C381DF.C4C54AA0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Greetings, =20 I did some searching around, and found the basic gas formulas at this = page- http://www.pmel.org/HandBook/HBpage20.htm =20 For my measured temps: =20 MAP / temp F / RPM 18" / 105 / 3000 20" / 128 / 4225 30" / 167 / 5000 36" / 196 / 5500 40" / 214 / 5700 44" / 228 / 5800 =20 It appears that at my 36" MAP boost level, I have the same air density = that I would have at NA, on the same 90F ambient day.=20 =20 Unfortunately, this air density is only part of the problem. I'm = guessing that exhaust backpressure is as much, if not more of an issue. This = leaves me still thinking that I'll need 5-6 psi of boost to break even with a = good NA engine, but I'm becoming more comfortable with those figures. =20 =20 Rusty (off to the hanger to see if I can find a place for Mr. = intercooler) =20 =20 ------=_NextPart_000_0001_01C381DF.C4C54AA0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
Greetings,
 
I did some = searching=20 around, and found the basic gas formulas at this page- =20
http://www.pmel.org/Ha= ndBook/HBpage20.htm
 
For my measured = temps:
 

MAP / = temp F /=20 RPM

18” / 105 /=20 3000

20” / 128 /=20 4225

30” / 167 /=20 5000

36” / 196 /=20 5500

40” / 214 /=20 5700

44” / 228 /=20 5800

 

It appears that at my 36" MAP boost level, I have the=20 same air density that I would have at NA, on the same 90F = ambient=20 day. 

 

Unfortunately, this air = density=20 is only part of the problem.  I'm guessing that=20 exhaust backpressure is as much, if not more of an = issue.  This=20 leaves me still thinking that I'll need 5-6 psi of boost to break = even with=20 a good NA engine, but I'm becoming more comfortable with those=20 figures.  

 

Rusty (off to the hanger = to see if I=20 can find a place for Mr. intercooler)  =

 
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